A long day in which I had one-to-one meetings with seven new MSc students - and all the associated admin - was book-ended by appearances in Q&A sessions at 08:00 and 19:00. These related to a talk I'd contributed to a course for a few hundred PhD students. Rather than being with them all in Berlin for what would have been a really enjoyable event, they were distributed around the world [Hence the two sessions.]. This evening I was sharing the floor with the most famous person in the world in my field, who had contributed three old videos of talks. I knew that most of the audience would want to hear him speak and have the chance to ask him questions, so I shut up and left him to it, although I was also somewhat intimidated. However, the moment came when he was making a mess of explaining a relatively simple issue, allowing me to dive in and give a concise intuitive answer that he acknowledged, was "what I was trying to say". Emboldened, I contributed more from then on. I'm still glad that it's over!